1. Field of the Invention
This invention is generally related to communication systems and in particular to wireless communication systems.
2. Description of the Related Art
Communication systems, and in particular, wireless communication systems usually have limited amounts of various resources that can be allocated to users of such systems. Examples of resources include the amount of power allocated to a signal to be transmitted, the amount of bandwidth allocated to a particular signal and the rate at which data is transmitted for a particular signal. As users request admission to a communication system, the system will admit the users if there are sufficient resources available to adequately service the requesting users. Requesting users typically specify to the communication system the type and amount of resources they desire. Requesting users (or user equipment) usually utilize one or more signaling channels to communicate their resource specifications to the communication systems.
Hereinafter, the terms ‘user’ and ‘user equipment’ will be used interchangeably. The resource specifications are typically various parameters (e.g., data rate, transmit power, bandwidth) that the user equipment (e.g., cellular telephone, wireless pager, wireless personal computer) transmit to the system equipment to allow the system equipment to determine whether there are sufficient resources available to properly service the requesting user equipment. The system equipment are typical communication equipment (e.g., transmitters, radios, amplifiers, modulators, processors) used in wireline or wireless communication systems. The system equipment are typically owned, operated and controlled by a service provider. The service provider is usually a commercial entity (e.g., local phone company, cable company, Internet service provider) that provides communication services to users. The signaling channels are communication channels reserved by the system for controlling communications between users and between users and system equipment. Various signaling information are conveyed (i.e., transmitted and/or received) between system equipment and user equipment over the signaling channels to properly initiate, maintain and terminate communications between users or communications between user equipment and system equipment.
The signaling channels are operated as per one or more protocols established from one or more standards with which the communication system complies. Protocols are specific rules that dictate how communications between users or communication between user equipment and system equipment are to be managed. Typically, a communication system admits users requesting admission or schedules users on a First Come First Serve (FCFS) basis. Admission to the communication system is the procedure taken by the system to allow a user to have access to and utilize various resources of the system so as to initiate and establish communications with system equipment or with other user equipment via the system equipment. Requesting users are put in a queue in the time order of their request and each is admitted to the system upon its turn if there are sufficient resources available to serve such user. When there aren't sufficient resources for the next requesting user, the system does not admit the requesting user until the sufficient amount of resources becomes available. Thus, a requesting user may have to wait in the queue for a relatively long period of time before it is admitted to the system. Further, one or more other users in the queue may have resource requirements that can be met by the current amount of resources available, but these users are not admitted because it is not their turn to be served; in this manner, the FCFS scheduling technique renders the system inefficient.
Many times, the type of information being conveyed (i.e., transmitted and/or received) by users of the system warrants the use of a scheduling technique other than the FCFS technique. For example, the nature of voice calls using Voice over IP (Internet Protocol) infrastructure is such that the application of the FCFS may lead to low quality voice communications. Further, in third generation wireless communication system (e.g., systems that comply with the 3G-1X Code Division Multiple Access (CDMA) standard), gradations of available resources are made available. For example, in 3G-1X systems, the data rate resource is divided into lower speed channels and higher speed channels for data calls. Data calls are communications established between two users or between user equipment and system equipment where the information being conveyed is data (e.g., digital data) that represent graphics, text, video or any other type of information. Voice calls are established communications between user equipment or between user and system equipment that convey mainly voice signals. In many instances the voice signals are represented as digital information. Voice calls are characteristically distinct from data calls in that data calls are usually time-delay tolerant. Any interruption in the flow of bits for voice traffic signals during an established communication (i.e., a call) would cause discernible noise and in some cases may even make the voice quality unacceptable at a receiving end. Established communications are arrangements and procedures that are implemented as per the protocol and/or standard being followed by the communication system to allow communication signals to be conveyed between system equipment and/or user equipment. What is therefore needed is a technique for efficiently allocating resources to different types of calls by users of a communication system.